The Washington Nationals, again steaming like a locomotive toward the postseason, have heard more about what they will lose than what they are. They may be tiring of it, of the bleating about the impending shutdown of Stephen Strasburg and the silence surrounding the man who Thursday night steamrolled the highest-scoring offense in the majors.

“People keep talking about Stras,” outfielder Jayson Werth said. “Edwin Jackson is a heck of a pitcher. He’s a big-game pitcher. Take Stras out and put Edwin in, I like it.”

The Nationals used their 8-1 romp over the St. Louis Cardinals to hammer home how much more they have than Strasburg. Start with Jackson, who recorded 10 strikeouts and allowed four hits in eight innings against the team with which he won last year’s World Series. The Nationals also have Werth, surging as a leadoff hitter atop a lineup that has regained its swagger. And they have Bryce Harper, who at 19 has managed to come out the other side of a two-month slump leaving vapor trails in all corners of Nationals Park.

Harper sparked the Nationals’ offense with a two-run homer in the first inning, a laser into the home bullpen, his third home run in two games. He later added a sweet RBI single and a running, over-the-shoulder catch in center. He batted behind Werth, who clobbered his first home run since coming back from a broken wrist, one of three times he reached base.

The victory, the second straight night the Nationals swatted 13 hits, put to bed the angst from their five-game losing streak and gave the Nationals an edge over a potential postseason foe. The defending champions entered Thursday with the best run differential in the major leagues, having outscored opponents by 113 runs. In their first meeting of the season, the Nationals smothered them with power on the mound and thunder at the plate.

“We know what we’re capable of doing,” Jackson said. “It’s not the first good team that we’ve played. We’ve played a lot of good teams this season. Everyone in here knows we’re capable of winning any game against team at any given chance.”

Harper was the catalyst. In the first inning, Harper came to the plate with Werth on base after a leadoff walk against Jaime Garcia. Nationals hitting coach Rick Eckstein and Johnson had implored Harper to keep his feet still, to not hack so hard his center of gravity shifts, to control his sound-barrier bat speed. The way for him to start hitting home runs was to stop trying.

“He’s all-in, all the time,” Johnson said. “But he’s gotten a little calmer with his lower half. He kind of can get real aggressive with his lower half, and he’s calmed down quite a bit.”

It worked Wednesday night, when he became the third teenager to launch two homers in one game. Thursday, he took two balls. Garcia threw him a 90-mph fastball over the outside. Harper waited, then unleashed his effortless and fierce hack. His feet barely moved, his hands rifling the bat through the zone.

“I just try to work as hard as I can up there and try to get a pitch I can drive,” Harper said. “I just try to stay within myself and play good ball.”

The ball zoomed as if propelled by rocket boosters. It never got more than 20 feet off the ground, and it may have torn a hole in the right field fence had it not gone over it, into the Nationals’ bullpen.

In his 75th career start, Garcia had allowed his fifth homer to a left-handed batter. Harper’s 15th home run this year gave him more as a teenager than every player in history except Ken Griffey Jr., Mel Ott and Tony Conigliaro.

The rest of Harper’s at-bats proved how much he had calmed down his swing, and, in one instance, himself. He crushed a 400-foot drive to center in the third inning, only for Cardinals center fielder Jon Jay to catch it as he eased into the padded fence. Harper removed his helmet after crossing first, but then smiled, peered at the sky and carried it back into the dugout.

“Bryce is a totally different animal,” Werth said. “He’s a special player. It’s unbelievable. When I was 19, I don’t know if I would have been ready for all this.”

Werth provided the other significant blow. There was no doubt about his first home run since May 5, before a broken wrist sidelined him for three months. The ball scorched off his bat and smacked off the back wall of the visitors’ bullpen in left-center field. Even if he has only four homers this season, Werth has been one of the Nationals’ most productive players, hitting .305 with a .389 on-base percentage and a .458 slugging percentage.

The onslaught was more than Jackson needed. Early on, the Cardinals couldn’t touch him. He recorded his first five outs by strikeout. By the end of the third inning, Jackson had struck out at least one Cardinals batter looking, swinging, foul-tipping and on a ball in the dirt with a throw to first. Jackson’s strikeouts pushed the Nationals’ staff total past 1,069, a new high since baseball returned to Washington with 32 games to go in the season.

The Cardinals could not have hit Jackson’s high-80s slider with an oar. Three times, they whiffed over balls in the dirt that required a catcher’s throw to first base. They could not look for a hard, biting slider in the high-80s, because Jackson also zipped his fastball from 94 to 96 mph. Jay gazed at one for strike three to begin the game.

“He knew he was going up against his old ballclub, and he really wanted to pitch a good game,” Johnson said. “Everyone could feel it and knew it.”

By the bottom of the seventh, Jackson strapped on his shin guard, helmet and batting gloves three hitters before his turn at the plate. “It was very obvious what he wanted to do,” Johnson said.

“The type of person I am, good or bad, I never want to come out of a game,” Jackson said. “I always want to go out and continue to battle for the team.”

Johnson let Jackson hit for himself, and he finished off the eighth despite a run-scoring throwing error by Ryan Zimmerman. Jackson stayed in for 123 pitches. He sauntered off the mound, a standing ovation from the remaining crowd washing over him. Only one shutdown, the one he executed on the Cardinals, had mattered.